Health Costs of Aging: Present and Future Trends: This sub-component aims to introduce direct costs of care into the discussion of the population impact of diseases. In developing countries, data sets from national insurance schemes are not available and it will first be necessary to develop methods for data collection for data collection. The long-term goal is to build an information base showing country variations in the direct costs of aging, but the short run goals are to: 1. estimate the expenditure on health care on people over 65, and the proportion of total national health care expenditures on people over 65, in 7 developing countries at various stages of the epidemiological and demographic transitions. 2. project these costs over time in the 7 countries using country level micro-level data on income elasticities of demand, and projections of changes in population size, structure, income and other socio-economic variables; 3. project these costs over time in the 7 countries based on estimating a multi country, multi time period model of the determinants in expenditure in people older than 65, and projections of population size and structure; 4. Undertake a validation study by comparing the predicted projected expenditures in selected OECD countries from a past baseline year using the two proposed methods- the cross-country age specific cost model, and the single country micro-level model. This cannot be done in the 7 developing countries due to a lack of histological data on these variables. 5. Devise a general method for estimating and predicting expenditures on health care on the population older than 65 years in lower-income countries.